Electric meter.



No. 679,333. Patented July 30, I901.

W H. PRATT.

ELECTRIC METER.

(Application filed Apr. 22, 1901.) (No Model.) 2 Sheets-Shaot I.

6 VOL T5 WLtnesses Inventor L li 01m r211:

No. 679,333. Patented July 30, I90l. W, H. PRATT. ELECTRIC WIETER.

(Application filed Apr. 22, 1901.)

2 Sheets-Shed z (No Model.)

Invgntoh William H.Pratt.

Wiine-sses.-

Rms PETERS 00.. mom-Limo" WASPHNGTQN. 'n. c.

nirnn Srarne arflnnrr @rrron.

VVILLIAMII. PRATT, OF LYNN, MASSACHUSETTS, ASSIGNOR TO GENERAL ELECTRICCOMPANY, OF NEW YORK.

ELECTRIC METER.

SPECIFICATION forming part Of Letters Patent NO. 679,333, dated July 30,1901.

- Application filed April 22, 1901. Serial No. 56,804:- (No model.)

T0 at whom it may concern:

Be it known that I, WILLIAM H. PRATT, a citizen of the United States,residing at Lynn, in the county of EssexJState of Massachusetts, haveinvented certain new and useful Improvements in Electric Meters, (CaseNo. 2,082,) of which the following is a specification.

In meters employed to register the energy consumed in circuits includinga storage battery it is desirable to provide for forward or backwardmovement, so as to indicate on a single dial the condition of thebattery from time to time. With meters ofv the Thomsonrecording-wattmeter type, in which an aux-- iliary starting-coil isemployed in the field to compensate for errors due to starting friction,means have been heretofore provided for changing the circuit connectionswith relation to two or more starting-coils, so as to compensate forthis friction in either direction of operation of the motor. Myinventionrelates to meters of this type; and it consists of a polarizedcontrolling device responsive to the work-current in the circuitcontrolling the meter for governing this starting friction, so as toinsure accuracy of the record.

In carrying out the invention I provide a polarized relay under thecontrol of the workcurrent and an electromagnetic switch for governingthe direction of assistance of the starting-coil.Therelaycomprisesamagnetic circuit, for which the magnetizing-current isfurnished by the work-current, and which therefore reverses its polaritywith the reversal of direction, accordingly as the storage battery ischarging or discharging, and'is provided on its pole-pieces with anopposing winding, giving a constant direction of magnetization. Thiswindingmaybeexcitedbyashuntcircuit from a part of the storage battery,if desired.

The novel features of the invention will be hereinafter more fullydescribed, and will be definitely indicated in the claims appended tothis specification.

In the accompanying drawings, Figure 1 shows diagrammatically a systemof meter connections embodying my improvements. Fig. 2 is a perspectiveview of a polarized controlling device.

1 represents the series coils, and 2 the armature, of ameter-motor-such, for example, as commonly employed in Thomsonrecording- Wattmeters, in which the armature is or may be excited by apotential circuit and a field cooperating with the armature by a fewturns in series with the work-current.

3 represents a storage battery, the amount of residual energy in whichit is desired to indicate.

4 represents a supply-'circuit for the battery, which may be controlledbya hand-operated or automatic switch, (typically indicated at 5.)

6 represents a motor,which might of course be any other type oftranslating device or devices fed by the storage battery.

In series relation to the battery are the series coils I, which are fedthrough heavy copper studs 7 7. The stud 7, as indicated in the diagram,passes through the iron core 8, and the magnetic field developed by thispartial turn of the stud which threads the magnetic circuit acts topolarize the core 8. The stud 7 furnishes magnetizing-current for a core8 of a magnetic device controlling the friction compensating coils. Thisfriction is regulated by coils 1O 10", one of which is wound in adirection to assist movement of the meter-motor in one direction and theother movement in the opposite direction.

The magnetic controlling devices maybe of any approved construction.That shown com prises two iron pole-pieces, as 11 11, secured to one legof the core of the instrument, between which plays an armature polarizedby the other leg, which acts as a relay-tongue to out into circuit oneor the other of the two contacts 12 12. One of these contacts connectswith the polarizing-coils 13 of a switchmagnet. The other contact l2'connects in like manner with the polarizing-coils 13 of a companionswitch-magnet.

9 9 are armatures cooperating with the coils 13 11. The other terminalsof the coil systems 13 13 connect in parallel with one of thecircuit-mains, the relay-tongue 14 being connected with the othercircuit-main. The

coils 11 11* are fed by a small group of cells from the storage battery.The starting-coils 10 10 are connected to the potential circuit ICC inwhich the armature is included, and this i may be derived from a smallgroup of cells one of which is in series relation to the coil 10 througha resistance 17 and the other with coil 1O through a resistance 17.

With this organization the operation of the system is as follows:Assuming the switch 5 to be in the position indicated in the drawings,the battery 3 is being charged from the supply-circuit 4 over a circuitincluding the switch 5, the battery, Wire 18, to one end of the stud 7,through the stud to its other end, and thence to a wire 19 leading tothe series field 1, thence to the stud 7"-, and by wire 20 to the returnside of the supply-circuit. The current passing through the stud 7 willpolarize the relay-magnet 8. The coils 11 11 of the relay, beingenergized by a shunt-circuit from a section of the storage battery 5give a determinate direction of movement to the relaytongue 1 lsaydownwardlythereby completing contact with 12 and putting thesupply-circuit on coils 13 through wire 21 22, thereby throwing theswitch 15 to complete connection with contact 16, and thus completingthe armature-circuit of the metermotor from one terminal of the group ofcells 3* through resistance 23 17, starting-coil 10, armature 2,conductor 24, to the other terminal of the group of cells 3. The motorthus will run in a direction to record the amount of energy absorbed bythe storage battery. If the switch 5 is opened and the circuit includingthe motor 6 or other translating device is closed, the currentdischarged by the storage battery will pass in a reverse directionthrough the series field l and through the stud 7, thereby giving anopposite polarity to the magnets energized by this stud and shifting therelay-tongue 14 to connect with the upper contact 12, thereby cutting inmagnet 13 of the switch for the starting-coils over the path 25, coils13, and wire 22. The switch 15 will thereby be shifted to engage withcontact 16, which cuts the starting-coil 10 into series relation to thearmature 2, being wound, as already stated, in a direction to assist thebackward movement of the meter-motor. The polarized instrument isresponsive to very light currents. Thus the meter-motor runs forward orbackward as the battery is charging or discharging, and the meter-dialwill indicate the energy in the battery at any time. The meter may beadjusted to run at a different speed in going backward to balance theinefficiency of the battery by giving the resistances 17 17 differentvalues.

What I claim as new, and desire to secure by Letters Patent of theUnited States, is-

1. The combination of a translating device and a relay governing itscircuit connections, the relay-armature being polarized. by a conducting-stud adjacent to its magnet-core in circuit with the translatingdevice.

2. An electric meter for storage batteries having its motor operated byseries and potential windings, starting-coils for compensating motorfriction in opposite directions of movement, and a polarized relayhavinga magnetic core polarized by the work-current for cuttingintooperation the respective starting-coils.

3. A meter provided with means to compensate for friction in oppositedirections of motor movement, a relay responsive to reversals ofwork-current, and a magnetically-operated switch governed by the relaycontrolling the compensating means.

1. A storage-battery meter provided with starting-coils to compensatefor friction in opposite directions of motor movement, a polarized relaycontrolling the respective coils, and a conducting-stud threading themagnetic circuit of the relay, said stud being connected in thework-circuit.

In witness whereof I have hereunto set my hand this 18th day of April,1901.

WILLIAM H. PRATT.

Witnesses:

DUGALD MoK. MoKILLoP, ALEX. F. MACDONALD.

